Treatment of internal-combustion-motor cylinders for carbon deposit



beams-9C1 Patented Aug. 30, 927.

UNITED STA'F s CROSS REFERENCE JOHN F. GANNING, OF RIC HMOND HILL, NEWYOK TREATMENT OF INTEBNAL-COMBUSTION-MOTOB CYLINDERS FOR CARBON DEPOSIT.

Thisinvention relates to the treatment of cylinders of internalcombustion motors to prevent, decrease, or remove the deposits whichordinarily form therein during the operation of the motor, commonlyreferred to as carbon; to reduce the tendency of the motor to knock fromthis cause, and to generally improve its operation. The inventioncomprises anovel composition of matter for the purpose and novel methodsof introducing the same and of preventing or reducing the carbonaceousdeposit in the cylinders.

In the operation of an internal combustion motor it is well known thatowing to the actual combustion of the fuel in the cylinders and the veryhigh temperatures resulting therefrom, there is a more or less rapidaccumulation of deposit in the combustion spaces of the cylinders,around the valves, and upon the spark plugs, which seriously intefereswith the proper operation of the motor. This deposit, commonly referredto as carbon, tends to cause pre-ignition of the fuel charge in thecylinder resulting in the phenomenon commonly called a carbon. knock.This trouble has been so serious with the present grades of fuel that ithas been necessary to design engines with materially lower compressionratios than would otherwise be desirable, which lowering of thecompression decreases the power obtainable from an engine of given size.This deposit in the cylinders also fouls the spark plugs and at timesrenders them inoperative; and it also lodges upon the valves and valveseats and frequently prevents tight closing of the valves. i Thisdeposit, while commonly referred to as carbon is not entirely carbon,but includes other foreign substances such as, in some instances, ironrust or metallic particles from the walls of thecylinder and piston, andgenerally a considerable portion of silica or other mineral matter dueto 'dust from the road being drawn into the cylinders with the airentering the carbureter. The carbon element of the deposit is formed bysoot resulting from incomplete combustion of the fuel, and also from acarbonization of the excess of lubricating oil which finds its way intothe combustion spaces of the cylinders. The formation of the sooty partof the deposit is increased if too rich a mixture of fuel and air isused in the cylinder, and the amount and character of this lubricatingoil may reach Application filed June 16,1928. Serial No. 645,916.

part of the deposit also varies with the constitutions of differenttypes of gasoline or other fuel which may be used. An excess of thecylinders if the pistons are too loose, or if the design or constructionof the pistons and rings is incorrect, or from other causes. Thelubricating oil which reaches the combustion spaces of the cylinders ismore or less decomposed by the high temperatures, and, in addition toitself providing a source of carbon, it appears when partiallycarbonized to act as a binder for the foreign elements in the cylinder,and under the high temperaturesit is consolidated with these otherelements into a cake'or crust which frequently clings with' greattenacity to the piston head, cylinder walls and valves. In someinstances this deposit is very hard and dry; and in other instances itis more or less soft and sooty, and frequently where there is an excessof oil reaching the engine cylinders, the deposit is greasy. The lattercondition is very objectionable, as it tends particularly to foul thespark plugs and prevent proper ignition.

The composition of matter which I prefer to employ in accomplishing theobjects sought by my invention includes an element, or elements, adaptedto be absorbed by the carbon deposit, and to have a solvent action uponthe ingredients of the deposit capable of being dissolved, especiallythe resinous or oily parts of the deposit which act as a binder for theother ingredients. This solvent element is also preferably of acombustible nature. Also included in the composition is an oxidizingagent, preferably one which will also have more or less of a solventaction, the primary purpose of the oxidizing agent being to cause thepartially dissolved and loosened carbon with the solvent element whichit has taken up, to burn under the high temperatures which occur in thecylinders during operation of the motor. For reasons which will beexplained, I prefer to use a composition which is readily soluble in thegasoline or other. petroleum fuel used, and which will not in any wayinterfere with the proper explosion of the combustible charge in thecylinder, but will, if anything, tend to improve the burning of thecharge. Such a composition may be introduced into the fuel and becarried into the cylinders with the fuel charge during the operation ofthe motor.

In its preferred form, my composition of FUEL & IGNITING DEVICES,

matter comprises entirely coal tar derivatives. The primarily solventpart of the composition consists of coal tar oils from which the taracids have been substantially removed, and preferably including elementshaving a distri utive range of boilmg points, the greater portion ofwhich preferably boils at a somewhat higher temperature than the largerpart of ordinary gasoline. 'A

' amount of heavier coal tar oil of the fraction sometimes referred toas coal tar creosote oil, and boiling approximately between 150 C. and350 C. As the primarily oxidizing agent of my composition, I may employa nitrated coal tar derivative or other aromatic nitro compound,preferably nitrobenzol (or oil of mirbane as it is called commercially).The portions of the different elements of my composition may beconsiderably varied, but as an example of a composition which I findhighly satisfactory, I may employ about 67% of the lighter coal taroils, about l of the hea coal tar oils, and about 28 72, of the nitroenzol, (percentages by volume). The nitrobenzol has a more or lesssolvent actionupon the carbon deposit in addition to its oxidizingaction, and the percentage of it employed may be considerably varied solong as enough is used to produce the desired oxidizing effect. Otheroxidizing agents ma be substituted for it, but nitrobenzol is esirable,because it appears to be the most effective for the purposes intended,because it does not contain inorganic substances which might leave aresidue, because it has a suitable boiling point and is not toovolatile, and because it is readily soluble in the petroleum fuelscommonly employed in internal combustion engines.

The coal tar oils mentioned are particularly suitable for the solventelement of my composition because they are very effective in eatin intothe carbon deposit by more or less direct solvent action on the oilybindmg elements of the deposit, and are readily combustible in thepresence of the oxidized agentso as to produce the burning off of thecombustible parts of the deposit. By using oils having different orgraded boiling points, it is possible to employ solvent -constituents ofhigh boiling point, which will not volatilize quickly, but will remainin contact with the deposit so as to penetrate more thoroughly, andproduce a more powerful action than is the case with more ighly volatileconstituents. The lighter iiross Reference constituents however, inaddition to their solvent and burning action, act as carriers for theheavier constituents, and enable them to more thoroughly permeate thedeposit. The presence of lighter elements also promotes the propervolatilization or atomizing of the heavier constituents when introducedwith the fuel into the carbureter and engine cylinders. Thelighterelements also carry the heavier into-the gasoline in the tank, andprevent such heavier elements from tending to separate out. Acharacteristic of the coal tar oils which makes them especially suitablefor the purpose is that they do not themselves tend to detonate in thecylinders. Other oils could for some purposes be substituted for thecoal tar oils mentioned; for instance, petroleum oils of similar boilingpoints can be employed, but are less eii'ective and would be lesssatisfactory, among other reasons because they would tend to themselvesincrease detonation in the cylinders.

Inmentioning the use of the difi'erent percenta es of the lighter andheavier coal tar oils, it will be understood that these percentages maybe varied in accordance with the characteristics of the particular oilsavailable. The high flash, solvent, or heavy naptha referred to, and theheavy coal tar oil, or coal tar creosote oil, having substantially theboiling points mentioned, are specified because readily obtainable inthe market. As it is desirable not to have too high a proportion of theheavier oils, a much greater percentage of the naptha fractions is usedthan the heavier fractions. It might be possible to obtain a single coaltar distillate containing the proper range of fractions for use in mycomposition, but under present commercial practice, the describedmixture is satisfactory.

My improved composition of matter may be introduced into the enginecylinders or brought in contact with the deposit in any suitable manner.For instance a small amount might be directly injected into eachcylinder, or into the manifold. I greatly prefer, however, and it is oneof the features of my invention, to introduce the substance into theengine cylinders by mixing it with the gasoline or other fuel before thesame passes through the carbureter to the engine. For instance, in anordinary gasoline operated automobile,-I merely pour a small amount ofthe composition into the gasoline in the ordinary storage tank. Theproportion of the composition to the fuel can be considerably varied andwill depend upon whether the composition is to be used in a new or cleanengine, primarily for the purpose of preventing the formation of acarbon deposit, or whether it is to be used in a very dirty engine, inwhich case, a larger proportion should be employed. Or-

Search Room dinarily I find that the use of one part of the compositionto about 640 parts of gasoline is sufiicient to procure satisfactoryresults in a new or clean motor, while under unfavorable conditions, Irecommend the use of one part of the composition to about 320 parts ofthe fuel. A somewhat larger amount of the composition may be employedfor certain conditions of carbon deposit without objectionable results.The composition may be employed steadily or may be used from time totime as needed, but I recommend that a small quantity of it be used atall times, preferably beginning before there is any deposit formed inthe motor.

My preferred composition being entirely and readily soluble in petroleumfuels, is readily carburettable with a petroleum fuel such as gasoline.-When used with such a fuel it passes directly into the engine cylinderswith the explosive mixture, and being somewhat less volatile than thegasoline it condenses more or less and is deposited on the walls of thecombustion space where it attacks the deposit thereon.

A very efiective method of causing the composition to be brought intointimate contact with the surface of the combustion space consists inintroducing the composition into the fuel as described and then, whenstopping the motor, actuating the carburetor choker so as to leave theengine cylinders completely filled with a very rich charge of fuel withthe composition carried thereby. This'provides a concentration of thecomposition sufiicient to cause it to act most effectively andthoroughly in permeating the carbon deposit while the engine is at rest.During this time, the soluble ingredients of the deposit will bedissolved or softened and u on starting the motor, the

softened and oosened parts of the de osit will be blown out by theexplosions ta ing place within the cylinders and the high temperatureproduced will cause the combustible parts of the deposit to burn.

My composition appears to be most effective under the action of heat andtherefore tends especially to keep the hottestthat when my compositionis used in a cylinder in which the deposit is of an oily nature, as whenthere is an excessive amount of lubricating oil reaching the combustionspace, this condition is quickly changed and the oiliness of the depositdisappears. This is particularly noticeable about the spark 'plugs whichwill be kept very clean.

For the purpose of improving the lubrication between the upper part ofthe pistons and the cylinder walls, where lubrication is ofteninsufiicient, particularly in new motors, I ma introduce into mycomposition a lubricating ingredient, such. for instances, as a smallamount of petrolatum or other heavy, non-volatile grease, soluble in thecomposition. A composition including such a lubricant may beadvantageously employed, for instance, while the motor is bemg operatedfor its first two thousand miles, after which the composition may beutilized without the grease. The introduction of the lubricant into theengine cylinders with the composition is particularly desirable becausethe composition prevents the lubricant from tending to objectionablycarbonize the motor and foul the spark plugs, a result which frequentlyoccurs when it is attempted to introduce lubricant only with the fuel.For like reasons the composition with a lubricant may be advantageouslyused in the fuel of small boat engines, motor cycle engines, or otherengines which are lubricated by introducing oil with the fuel.

The ingredients which I have mentioned as preferred for use in mycomposition are the most effective now known to me for the purpose, butit will be understood that other suitable ingredients capable ofproducing the same, or similar action, may be substituted.

What I claim is:

1. A- petroleum fuel additioned by a relatively small quantity of acarbon removing agent, consisting of coal tar distillates, from whichthe tar acids have been substantially removed, a relatively largeportion of said distillates boiling between 130225 (3., and an oxidizingagent comprising a nitrated cyclic h drocarbon soluble in saiddistillates and sai fuel.

2. A composition of matter for treating internal combustion enginecylinders for carbon, consisting of a coal tar distillate boilinapproximately between 130 and 225 i, approximately 67%; coal tardistillate boiling approximatel between 150 and 350 0., approximate y 492,; an nitrobenzol approximatel 28 75.

In testimony whereof I have affixed my signature to this specification.

JOHN F. CANNING..

